HOMER User Case Study: SAFT

The following case study is adapted from a presentation given at the 2016 HOMER International Microgrid Conference. SAFT‘s Stuart Lansburg spoke to attendees about cold-weather storage and SAFT’s approach to these high-tech battery storage systems, presenting two case studies and a critique of HOMER Pro performance.

Importanceofstorageinremote cold-weather microgrids

When utilized in remote northern microgrids, storage systems enable a high penetrationofrenewables, producing fuel savings and a return on investment despite the 10% of all energy that is lost passing through ESS. Batteries must be kept small, but not so small as to age prematurely. To reap the rewards of storage, operators should alwaysoperatedieselsatpeakefficiency, in baseload mode, and operate the grid with diesels off.

Storage systems should include a grid-formingconverter and Li-ion NCA chemistry for high efficiency and the ability to operate permanently at partial SOC. A ‘cold-weather’packageforArctic conditions requires high tech insulation for the container and hydronic coil for heating with glycol from the diesel plant.

The community’s diesel power plant was designed with a load capacity of between 35kWand150kW, which it wished to augment with solar PV. SAFT, a HOMER Pro Gold Partner, performed numerous simulations to help size the PV expansion and analyze fuel consumption. The added renewable energy augments diesel power with50kWofPV,expandedto136kW. SAFT’s storage solution has been found to reduce the community’s diesel consumption by80,000 litersperyear.

Casestudy–KotzebueElectric

Kotzebue Electric (KEA)operatesawind-dieselhybridpowersystem with an averageloadof 2500kW and a maximum of 3500kW. Six diesels produce 725kWto3080kW and 19windturbinesadd 2940kWtotal. Storage is key for this system as it reduces curtailmentofexistingwindturbines, and offers fastfrequencyresponseforoutagemitigation. Storage reduces the useofdieselpeakingunits, allowsdiesel-offoperation, and increasespenetrationofrenewables. Bottom line: storage reduces fuel costs.

SAFT: HOMER Pro ‘ideal tool’ for extreme cold modeling

Storage provides opportunitiesfordeployinghybrid powering in remote Alaskan and Canadian communities, but authorities require a business plan before securing funding. HOMER Pro istheidealtool for this purpose, providing detailedresultswithlimitedinputs. HOMERProprovidesahigh-levelapproachtoESS sizing, offering varyinglevelsofinputdetail and enabling the building of afinancialmodel.

“The Colville Lake and KEA projects are demonstrating what fuel savings can be achieved with large scale deployments of renewables with storage,” concludes SAFT’s Jim McDowell. “Now, opportunities are coming up with other villages. That is where HOMER Pro comes into its own, allowing us to propose less-conservatively sized systems with limited data.”